Carotid Baroreflex of Leg Vasculature

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dc.contributor.advisorPeter A. Raven
dc.contributor.committeeMemberH. Fred Downey
dc.contributor.committeeMemberPatricia A. Gwirtz
dc.creatorKeller, David Melvin
dc.date.accessioned2019-08-22T21:40:30Z
dc.date.available2019-08-22T21:40:30Z
dc.date.issued2004-07-01
dc.date.submitted2013-09-13T08:54:07-07:00
dc.description.abstractKeller, David Melvin, Carotid Baroreflex Control of Leg Vasculature. Doctor of Philosophy (Biomedical Science), July 2004; 110 pp; 5 tables; 10 figures; bibliography. The carotid baroreflex (CBR) exerts control of arterial blood pressure primarily as a result of changes in total vascular conductance. In humans, understanding CBR control of the vasculature supplying a given vascular bed, such as the leg, remains unclear. Furthermore, it appears that metabolic attenuation of sympathetic vasoconstriction may modulate the CBR of the vasculature supplying contracting skeletal muscle during exercise. However, the balance between baroreflex-mediated vasoconstriction and the mechanisms responsible for the metabolic attenuation has not been fully elucidated. Therefore, the purpose of the investigations within this dissertation was to: i) explain CBR control of leg vascular conductance (LVC) and the relationship between changes in LVC and muscle sympathetic nerve activity at rest and during one-legged knee extension exercise, ii) examine the CBR control of the vasculature supplying an exercising leg and a non-exercising leg during exercise, and iii) demonstrate the role of the ATP-sensitive potassium channel in contributing to the metabolic attenuation of CBR-mediated vasoconstriction in the vasculature supplying contracting skeletal muscle. In the first investigation, we demonstrated: i) the stimulus response relationships for CBR control of LVC and MSNA at rest and during two intensities of one-legged knee extension exercise; ii) that CBR control of LVC was preserved during exercise; iii) that the attenuation of CBR-mediated vasoconstriction was no different between 7W and 25W exercise in the vasculature supplying an exercising leg; and iv) that the contribution of changes in LVC to CBR changes in mean arterial pressure was no different from rest to exercise in both the exercising leg and the non-exercising leg. In the second investigation, we examined the role of the ATP-sensitive potassium channel in modulating sympathetically-mediated vasoconstriction at rest and during exercise in the vasculature supplying an exercising leg and a non-exercising leg. The attenuated vasoconstrictor response to the carotid baroreceptor stimulated hypotension observed in the vasculature supplying an exercising leg was partially restored two to four hours after the oral ingestion of glyburide (5mg). This finding indicates that ATP-sensitive potassium channel activation plays a primary role in the effects of functional sympatholysis during leg exercise in humans. We further demonstrated that CBR control of MAP was not altered by oral glyburide administration in healthy subjects.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/20.500.12503/29503
dc.language.isoen
dc.provenance.legacyDownloads0
dc.subjectBiology
dc.subjectBiomechanics
dc.subjectCardiovascular System
dc.subjectComparative and Evolutionary Physiology
dc.subjectExercise Physiology
dc.subjectExercise Science
dc.subjectKinesiology
dc.subjectLife Sciences
dc.subjectMedical Physiology
dc.subjectMedical Sciences
dc.subjectMedicine and Health Sciences
dc.subjectOther Kinesiology
dc.subjectOther Rehabilitation and Therapy
dc.subjectRehabilitation and Therapy
dc.subjectCarotid baroreflex
dc.subjectcontrol
dc.subjectleg vasculature
dc.subjectarterial blood pressure
dc.subjectvasoconstriction
dc.subjectATP
dc.titleCarotid Baroreflex of Leg Vasculature
dc.typeDissertation
dc.type.materialtext
thesis.degree.departmentGraduate School of Biomedical Sciences
thesis.degree.disciplineBiomedical Sciences
thesis.degree.grantorUniversity of North Texas Health Science Center at Fort Worth
thesis.degree.nameDoctor of Philosophy

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